This invention relates to braiding machines, and more particularly to a braiding machine having constrained layer noise dampening means to reduce the braider noise.
In the manufacture of such products as high pressure hydraulic or pneumatic hose, wire is tightly woven over a tubular mandrel or core in cooperation with layers of gum to form layers of braided sheath about the hose. The winding or braiding of textile core or wire is achieved by moving a tube or mandrel longitudinally while moving a plurality of bobbins mounted on carriers circumferentially around the tube in crisscrossing fashion as a maypole. These paths are two generally circumferentially extending sinuous paths which crisscross each other. The parts are created on a vertically disposed deck which has crisscrossing or sinuous paths. The deck has a front and rear deck plate, with the front deck plate having an inner plate, a quoit or oval plate and an outer plate, all interconnected to the rear deck plate. The inner and outer plates in cooperation with the quoit define a pair of crisscrossing sinuous grooves in which the carriers travel. Each carrier has a stub which is moved or handed off from one geneva gear to another geneva gear as other gears drive the geneva gear. The geneva gears are mounted on shafts that interconnect the quoit to the rear deck plate. The web of the carrier acts as a cam in the front deck plate groove to move the carriers along the fixed sinuous path. The respective carriers support spindles or bobbins of yarn or wire and as they crisscross each other they braid the strands of yarn or wire onto the central longitudinally movable mandrel.
A major problem with such braiding machines is that the noise level is very high as to be irritating and injurious as well as illegal in view of the noise limits being set by the Occupational Safety and Health Administration (OSHA). Therefore, noise suppression is desirable in the design of machines. In the case of the horizontal braiding machine the noise level is intense through the turning of the geneva gear between two deck plates and through a plurality of circumferentially extending and meshing gears. In addition to these noises, the spindle carriers being propelled along a metal track in a crisscrossing braiding pattern results in a further generation of a high noise level as the carrier is transferred, propelled or thrown from one guiding slot to another. A further source of noise is the vibration due to the suspension of the metal parts such as the quoit and outer deck as the carriers are moved thereby. Additional sources of noise is the effect of gravity pulling down on the carriers trying to pull the carrier out of the front of the deck, and the centrifugal force trying to throw the carrier away from the geneva gear or wheel into the edge of the deck. In addition, the tension of the wire or yarn required to make the correct lay onto the hose being fabricated can result in an additional force of as much as 40 pounds on some wire hose constructions. It being understood that there is considerably more tension required and demanded of a braiding machine fabricating a high pressure hydraulic hose which may have to withstand a burst pressure of 18,000 psi in comparison to the fabrication of items such as shoe laces, jump rope and candle wicks.
Sound measurement is usually expressed in dB (decibels), a relative quantity based on a reference power of 10.sup.-12 Watts. Sound intensity is the average rate of sound energy transmitted through a unit area normal to the wave direction at the point considered. This is a definition of power and may be expressed in watts per square meter. It is usual however to express power in decibels, dB or db, which is a term used to give the relative magnitude of two powers by comparing the one under consideration to a standard. At the threshold of hearing the sound power level is 0 db. At the other end of the scale, a 140 db is the threshold of pain. The human ear does not perceive an increase in sound pressure level as a proportionate increase in loudness. Moreover, the ear does not respond equally to all frequencies. Therefore, a frequency weighted scale called dbA or dBA is often used in noise studies to simulate human hearing response in the audible range from 20 to 20,000 Hz. In dBA units sound pressure measured in db or dB is scaled according to a frequency-response curve determined by international acoustic standards.
The present invention is directed to the layer damping of the decks, including the inner deck, quoit and outer deck. In addition, the carrier has the layer dampening applied thereto to thereby substantially reduce the noise level. The alternatives to Applicant's method and apparatus is to construct a housing to encompass the braider decks; however, this presents problems in servicing the decks and to properly observe and correct malfunctions. In certain instances, there is an insufficient amount of clearance space between adjacent braiding machines and to install housings would require the relocating of the braider machines or to reduce the number of braider machines in a shop.